Seeing a spider close by should set off alarms for many insects, but the Red Spotted Ant Mimic Spider reaps the benefits of good behavior.

The Red Spotted Ant Mimic Spider acts like an ant to gain better positioning when attacking prey. It walks on its back 6 legs while raising the front pair as if they were antennae. This behavior relaxes other ants and insects into thinking the spider's presence is nothing to worry about. It allows the spider to get close to its prey, making it easier to kill and eat.

Adults spin sacs for themselves to rest in. These silken sacs are hidden near anthills or colonies somewhere either in a leaf, in bark cracks or on a node (where a new branch or tree starts growing). They can be found in a variety of habitats including woods, under stones, on shrubs or in parks.

Females use their spider silk to wrap eggs in a sac. They then attach the shiny egg sac to a rock or stone for safe-keeping. Spiderlings overwinter and hatch in the spring, leaving their siblings to find their own way.

Basic Information

Common Name: Red Spotted Ant Mimic Spider

Scientific Name:Castianeira descripta

Category: Spider

General Identification

Size (Adult; Length): 5mm to 10mm (0.20in to 0.39in)

Identifying Colors: black; red; white

Additional Descriptors: hairy, biting, venomous

Taxonomic Hierarchy

Kingdom:Animalia

Phylum:Arthropoda

Class:Arachnida

Order:Araneae

Family:Corinnidae

Genus:Castianeira

Species:descripta

Spider Anatomy (Typical)

1

Legs: Spiders have four pairs of legs and these are attached to the cephalothorax.

2

Pedipalps: Small appendages near the mouth used as taste and smell organs.

3

Cephalothorax: Contains eyes, head, mouthparts, and legs.

4

Abdomen: Contains various organs related to digestion, reproduction, and web-making.

5

Spinnerets: Used in the production of spider silk for fashioning webs or catching prey.

NOTE: Unlike insects, spiders have both an endoskeleton (internal) and exoskeleton (external).

Territorial Reach (A-to-Z)

Note: An insect's reach is not limited by lines drawn on a map and therefore species may appear in areas, regions and/or states beyond those listed below as they are driven by environmental factors (such as climate change), available food supplies and mating patterns. Grayed-out selections below indicate that the subject in question has not been reported in that particular territory. U.S. states and Canadian provinces / territories are clickable to their respective bug listings.

The map below showcases (in red) the states and territories of North America where the Red Spotted Ant Mimic Spider may be found (but is not limited to). This sort of data can be useful in seeing concentrations of a particular species over the continent as well as revealing possible migratory patterns over a species' given lifespan. Some species are naturally confined by environment, weather, mating habits, food resources and the like while others see widespread expansion across most, or all, of North America.